Coupling arrangements are used when radioactive liquids are drawn off from a storage tank into a transporting container. If the radioactive liquid has to be taken out of a storage tank and filled into a transporting container, then the tank has to be connected to the container by pipe conduits. The two conduits are connected by a coupling arrangement which includes two coupling units. One unit is mounted on a flexible pipe conduit connected to the transporting container. The other unit may be fixed externally in a wall of the shielding cell, in the cover of the storage tank, in the wall of the tank or at the end of a pipe conduit connected to the tank. The two coupling units are put together and joined by suitable clamping members. There is a shut-off device in the form of a ball valve in each of the two coupling units to block the conduit corresponding thereto.
When the radioactive liquid is drawn off, it impinges on the inside of the coupling unit so that the coupling units are contaminated when they are uncoupled. For this reason, coupling units with shut-off devices have already been provided which, after the connection has been interrupted and the shut-off devices are in the closed position, do not have any externally exposed surfaces that have come into contact with the radioactive materials which flowed through the coupling unit while the unit was in use. However, these coupling units are of very complex configuration and are very expensive.
A coupling arrangement of the type described above is disclosed in German published patent application No. DE-OS 24 47 357. With the use of this coupling arrangement, it is intended that there be no contact with the toxic materials once the coupling unit has been separated. According to the solution disclosed, this is achieved by providing a connection for a rinsing medium pipe in each shut-off device. The shut-off devices in this arrangement are in the form of ball valves. Before the coupling arrangement is separated, the inner parts of the two coupling units are rinsed, thereby cleaning the parts of the unit which have come into contact with the medium conveyed.